Dental materials having low polymerization shrinkage

ABSTRACT

The present invention relates to dental materials composed of calix[n]arenes and also to the use thereof for cements, composites, adhesives and coating materials in the dental field. The materials include (a) 0.5 to 90% by weight of at least one polymerizable calix[n]arene according to formula (I), (b) 0.01 to 5% by weight of initiator, (c) 0 to 90% by weight of at least one additional monomer which can polymerize under cationic and/or radical conditions and/or which can polymerize by ring opening, (d) 0 to 85% by weight of filler, (e) 0.01 to 5% by weight of additive and (f) 0 to 70% by weight of solvent.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to dental materials comprisingcalix[n]arenes having low polymerization shrinkage and comparablemechanical properties.

2. Description of the Related Art

Calix[n]arenes are cyclic oligomers, known as 1_(n)-metacyclophanes(Scheme 1, formula 1), which are accessible by condensation ofp-alkylphenols with formaldehyde (Scheme 1, formula 2) or of resorcinolwith aldehydes (Scheme 1, formula 3), the phenolic OH groups beingarranged in the endo (intraannular) or exo (extraannular) position. Inthis connection, the particular bowl- or cup-like conformation of thecalix[n]arenes has resulted in numerous applications in catalysis,chromatography, analysis or sensor technology (V. Böhmer, Angew. Chem.,107 (1995), 785-818).

Scheme 1: 1: 1_(n)-metacyclophanes, 2: calix[n]arene of a p-substitutedphenol and 3: calix[4]resorcarene

Quite a number of papers on the synthesis and polymerization ofpolymerizable calix[n]arenes are known from the scientific literature.Examples of this are the synthesis of the radically polymerizable5-[3-(methacryloyloxy)propyl]-25,26,27,28-tetrabutoxycalix[4]arene (D.M. Gravett and J. E. Guillet, Macromolecules, 29 (1996), 617-724) or of5-(1-(acryloyloxypropyloxymethyl)-25,26,27,28-tetra(2-ethoxyethyl)calix[4]arene(M. T. Blanda and E. Adou, Polymer, 39 (1998), 3821-3826), the synthesisand radical polymerization of p-alkylcalix[6]arenes having (meth)acrylgroups, such as, e.g., the hexa(meth)acrylates of p-methyl- orp-tert-butylcalix[6]arene, (M. Iyo, K. Tsutsui, A. Kameyama and T.Nishikubo, J. Polym. Sci., Part A: Polym. Chem., 37 (1999), 3071-3078)or the synthesis of cationically polymerizable calix[n]arenes, such as,e.g., of5,11,17,23,29,35-hexamethyl-37,38,39,40,41,42-hexakis(allyloxy)calix[6]arene(T. Nishikubo, A. Kameyama, K. Tsutsui and M. Iyo, J. Polym. Sci., PartA: Polym. Chem., 37 (1999), 1805-1814).

The use of calix[n]arenes in combination with polymerizable formulationsis known from the patent literature. Thus, e.g., U.S. Pat. No.4,636,539, U.S. Pat. No. 4,718,966, U.S. Pat. No. 4,912,183, EP 235 935and FR 2 795 077 describe the use of calix[n]arenes, not modifiedreactively, as accelerators for cyanoacrylate adhesives.

U.S. Pat. No. 4,699,966 describes calix[n]arenes functionalized withacrylate or methacrylate groups and polymers thereof as sequesteringagents for metal ions. Additional, more specific, polymerizablecalix[n]arene and oxacalixarene derivatives with at least one phenolicside group are described in U.S. Pat. No. 5,216,185.

JP 09-263560 describes calix[n]arene derivatives which arefunctionalized with (meth)acrylate, vinyl or propenyl groups and can bepolymerized thermally or photochemically. JP 11-043524 describes similarsystems which, however, are additionally modified with polyalkyleneoxide groups.

WO 2005/075398 A1 and JP 2002-088007 describe polymerizablecalix[n]arene derivatives which result, in curable photoresists, in animproved resistance to heat. JP 2004-137395 claims a cellulose acrylatefilm comprising a polymerizable calix[n]arene derivative with theadvantage of improved mechanical and optical properties.

JP 2002-003563 and JP 09-263560 describe calix[n]arene derivativescomprising polymerizable groups (acrylate, methacrylate, vinyl, vinylether, and the like) and acid or anhydride groups. These find use asetching resists, adhesives, lacquers or coatings.

GB 2 185 261 describes a radically polymerizable composition as adhesivefiller comprising a calix[n]arene derivative. JP 02-124850 describes thepreparation of calix[n]arene derivatives by heatingp-tert-butylcalix[6]arenes with glycidyl methacrylate andtri(n-butyl)amine. U.S. Pat. No. 4,617,336 and CA 1 273 954 describecalixarenes with acrylate groups for the stabilizing of organicmaterials, in particular polymers.

JP 2000-256362 describes polymerizable calix[n]arene derivatives whichare functionalized with spiroorthoester groups. These compounds, whichare distinguished by a polymerization without shrinkage in volume, aresuitable, inter alia, for use as coating materials.

JP 2000-264953 describes, finally, curable epoxy resins which acquireadvantageous properties by addition of calix[n]arenes, such as a highcrosslinking density, high resistance to heat and good mechanicalproperties.

WO 2005/120229 describes substances which release terpenes and/oraromatic alcohols. The substances and compositions depicted can, interalia, also comprise calix[n]arenes and are used, first and foremost, toprevent microorganisms from adhering to surfaces. By way of example,compositions are described which prevent the development ofmicroorganisms in jointing compounds. Likewise, the use of compositionscomprising calix[n]arene for the cleaning of prostheses is described.

U.S. Pat. No. 4,699,966 describes calix[n]arenes and polymers preparedtherefrom, the calix[n]arenes being mixed with an initiator andpolymerized using light. The use as filler-comprising dental material oras component in such materials is not described.

U.S. Pat. No. 6,117,944 A describes the preparation and thedetermination of the reactivity of various calixarene-comprisingfiller-free compositions. The use in dental materials is not asubject-matter of this patent application.

EP 1 712 537 A1 describes a multitude of different calix[n]arenes indifferent compositions. These, though, comprise no filler and noadditional radically polymerizable components.

EP 432 990 A2 describes filler-free compositions for the masking andcoating of metals. The materials are cured from a solution using actinicradiation. Filler-comprising dental materials with calix[n]arene are notdisclosed.

EP 196 895 B1 describes filler-free adhesive compositions which containno filler. The polymers produced comprise calix[n]arene sequences.

WO 2005/056741 A1 describes non-stick compositions. These are devoid offiller and have, as coating, even for prostheses and dental or oral careproducts, no direct reference to dental materials, which concernmaterials for the preservation or reconstruction of the masticatoryapparatus. Filler-comprising compositions for dental use are notdisclosed.

WO 94/15907 A1 describes calix[n]arenes comprising cyano groups whichare used devoid of filler and for which a slight shrinkage was observed.Filler-comprising dental materials are not disclosed.

SUMMARY OF THE INVENTION

Therefore, it is the object of the invention to make available dentalmaterials which, in comparison with the conventional materials based onnormal methacrylates, are distinguished by a lower polymerizationshrinkage and good mechanical properties and, in addition, allowadditional advantageous properties, such as, e.g., self-adhesion, to beobtained.

This object is achieved by dental materials which exhibit the followingcomponents or are composed of the following components:

-   -   (a) 0.5 to 90% by weight, particularly preferably 0.5 to 40% by        weight, of at least one polymerizable calix[n]arene according to        formula (I),    -   (b) 0.01 to 5% by weight, particularly preferably 0.01 to 2% by        weight, of initiator,    -   (c) 0 to 90% by weight, particularly preferably 1 to 70% by        weight, of at least one additional monomer which can polymerize        under cationic and/or radical conditions and/or at least one        additional monomer which can polymerize by ring opening,        (meth)acrylates which can polymerize by ring opening or        polyfunctional (meth)acrylates being preferred,    -   (d) 0 to 85% by weight, particularly preferably 3 to 80% by        weight, of filler and    -   (e) 0.01 to 5% by weight, particularly preferably 0.01 to 3% by        weight, of additive,        the percentages each time adding up to 100%.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of the disclosure. For a better understanding of the invention, itsoperating advantages, specific objects attained by its use, referenceshould be had to descriptive matter in which there are describedpreferred embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Use is preferably made, according to the invention, of calix[n]arenes ofthe general formula (I):

in which

-   -   n=1 to 5,    -   R¹-R⁴=independently of one another, H, a C₁- to C₁₅-alkyl        radical which can be interrupted by O, a phenyl radical or a        benzyl radical,    -   X¹ represents a group with the structure: Y¹—R_(a) ¹(Y_(a)        ¹—R_(b) ¹—PG¹)_(m), in which    -   Y¹=not present or O, ester, amide or urethane,    -   R_(a) ¹=an m-valent organic radical which can comprise from 1 to        30 carbon atoms and, if appropriate, also from 0 to 6        heteroatoms, such as O, S or N,    -   m=1 to 3,    -   Y_(a) ¹=not present or O, ester, amide or urethane,    -   R_(b) ¹=not present or a C₁-C₁₆-alkylene radical which can be        interrupted by oxygen atoms,    -   PG¹=a polymerizable group, e.g. a group which can polymerize        under radical conditions, such as (meth)acrylate,        (meth)acrylamide, vinyl, allyl or styryl; a cyclic group which        can polymerize under radical conditions by ring opening, such        as, e.g., the groups        or a group which can polymerize under cationic conditions, such        as, e.g., a vinyl ether or glycidyl group, a cycloaliphatic        epoxide or oxetane group or a polymerizable nitrone group, with

Y_(b) ¹=not present or O, ester, amide or urethane,

-   -   R_(c) ¹, R_(d) ¹=independently of one another, C₁- to C₁₅-alkyl        radical which can be interrupted by O, a phenyl radical or a        benzyl radical;        -   and with furthermore    -   X²-X⁴=independently of one another, not present, OH or C₁- to        C₁₀-alkyl radical and which can have, independently of one        another, the same meaning of X¹ and, in addition, can represent        a group with the structure: (Y_(a) ²—R_(b) ²-AG)_(p), in which    -   Y_(a) ²=not present or, if appropriate, O, ester, amide or        urethane,    -   R_(b) ²=a p-valent organic radical which can comprise from 1 to        20 carbon atoms and, if appropriate, also from 0 to 4        heteroatoms, such as O or N,    -   p=1 to 3 and    -   AG=an anchoring group, such as, e.g., —P═O(OH)₂, —O—P═O(OH)₂,        —COOH or —O—SO₂OH.

Particular preference is given to polymerizable calix[n]arenescorresponding to the general formula (I) in which the variables of thegroups indicated above have the following meanings, it being possiblefor these meanings to be chosen independently of one another:

-   -   n=1 to 3,    -   R¹-R⁴=independently of one another, H, a C₁- to C₁₀-alkyl        radical which can be interrupted by O, or a benzyl radical,    -   X¹ represents a group with the structure: Y¹—R_(a) ¹(Y_(a)        ¹—R_(b) ¹—PG¹)_(m), in which    -   Y¹=not present or O or ester,    -   R_(a) ¹=an m-valent organic radical which can comprise from 1 to        15 carbon atoms and, if appropriate, also from 0 to 3 oxygen        atoms,    -   m=1 to 2,    -   Y_(a) ¹=not present or O or ester,    -   R_(b) ¹=not present or a C₁-C₁₆-alkylene radical which can be        interrupted by oxygen atoms,    -   PG¹=a polymerizable group, e.g., a group which can polymerize        under radical conditions, such as (meth)acrylate or        (meth)acrylamide, a cyclic group which can polymerize under        radical conditions by ring opening, such as, e.g., the groups        or a group which can polymerize under cationic conditions, such        as, e.g., a cycloaliphatic epoxide or oxetane group or a        polymerizable nitrone group, with    -   Y_(b) ¹=not present or O, ester or urethane,    -   R_(c) ¹, R_(d) ¹=independently of one another, C₁- to C₅-alkyl        radical, a phenyl radical or a benzyl radical; and with        furthermore    -   X²-X⁴=independently of one another, not present or C₁- to        C₁₀-alkyl radical and which can have, independently of one        another, the same meaning of X¹ and, in addition, can represent        a group with the structure: (Y_(a) ²—R_(b) ²-AG)_(p), in which    -   Y_(a) ²=not present or O or ester,    -   R_(b) ²=a p-valent organic radical which can comprise from 1 to        10 carbon atoms and, if appropriate, also from 0 to 2 oxygen        atoms,    -   p=1 to 2 and    -   AG=an anchoring group, such as, e.g., —P═O(OH)₂, —O—P═O (OH)₂,        —COOH or —O—SO₂OH.

The calix[n]arenes of the general formula (I) used according to theinvention can be obtained, starting from suitably functionalizedcalix[n]arenes, by reaction with appropriate polymerizable compoundscomprising acid groups. Thus, e.g., homogeneously substitutedpolymerizable calix[n]arenes can be prepared by modifyingHO-functionalized calix[n]arenes with methacryloyl chloride:

A concrete example is the preparation of the hexamethacrylate ofp-tert-butylcalix[6]arene:

Nonhomogeneously substituted polymerizable calix[n]arenes can beanalogously prepared by modifying HO-functionalized calix[n]arenes withmixtures of polymerizable acid chlorides, such as, e.g., methacryloyland acryloyl chloride. Furthermore, polymerizable calix[n]arenescarrying additional acid groups can be synthesized by sequentialreaction, e.g. polymerizable calix[n]arenes with dihydrogenphosphategroups by partial reaction with methylacryloyl chloride, followed byphosphorylation with phosphoryl chloride.

Suitable functionalized calix[n]arenes for the synthesis of thepolymerizable calix[n]arenes according to the invention corresponding tothe general formula (I) are known from the literature; a survey thereofcan be found in the review by V. Böhmer (Angew. Chem., 107 (1995),785-818). In accordance with this, a distinction is made between, on theone hand, one-pot processes, in which, e.g., tert-butylphenol is reactedwith formaldehyde under alkaline conditions, depending on thetemperature and the amount of base, to give the tetra-, hexa- oroctamer. On the other hand, differently substituted calixarenes can besynthesized stepwise by alternating hydroxymethylation and condensationsteps and, finally, subsequent cyclization of the linear oligomers thusobtained.

Suitable functionalized cyclic monomers for the synthesis ofcalix[n]arenes of the general formula (I) which can polymerize underradical conditions by ring opening are known from the literature. Forexample, the synthesis of vinylcyclopropanes and of bicycliccyclopropylacrylates is described by N. Moszner et al., Macromol. Rapid.Commun., 18 (1997), 775-780, or A. de Meijere et al., Eur. J. Org.Chem., 2004, 3669-3678. The synthesis of functionalized cyclic allylsulphides has been published by R. A. Evans and E. Rizzardo in J. Polym.Sci., Part A. Polym. Chem., 39 (2001), 202-215; Macromolecules, 33(2000), 6722-6731.

The calix[n]arenes corresponding to the general formula (I) which canpolymerize under radical conditions used according to the inventionallow the preparation of dental materials which, in comparison with theconventional materials based on normal dimethacrylates, aredistinguished by a lower polymerization shrinkage and good mechanicalproperties and, in addition, it is possible, e.g. by the use ofcalix[n]arenes corresponding to the general formula (I) which canpolymerize under radical conditions and which comprise acid groups, toobtain additional properties, such as, e.g., self-adhesion.

Accordingly, the materials according to the invention find use asself-adhesive dental materials, e.g. filling composites, cements andcoating materials. Likewise, the dental materials according to theinvention can be used as adhesives.

Even if the use of the compositions according to the invention isfocused on the use in the dental field, these materials have a broadrange of uses, e.g. they can be used as protective and masking lacquersfor optics, electronics and the motor vehicle industry.

The calix[n]arenes corresponding to the general formula (I) which canpolymerize under radical conditions used according to the invention canbe used in a mixture with conventional monomers which can polymerizeunder radical conditions, in particular with difunctional (meth)acrylatecrosslinking agents. Suitable with regard to this are in particularcrosslinking di- or polyfunctional acrylates or methacrylates, such as,e.g., bisphenol A di(meth)acrylate, Bis-GMA (an addition product ofmethacrylic acid and bisphenol A diglycidyl ether), UDMA (an additionproduct of 2-hydroxyethyl methacrylate and 2,2,4-trimethylhexamethylenediisocyanate), di-, tri- or tetraethylene glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, pentaerythrityltetra(meth)acrylate, and 1,4-butanediol di(meth)acrylate,1,10-decanediol di(meth)acrylate or 1,12-dodecanediol di(meth)acrylate.

Particularly advantageous is the use of the calix[n]arenes correspondingto the general formula (I) which can polymerize under radical conditionsin a mixture with known monomers which can polymerize under radicalconditions by ring opening with little shrinkage, such as, e.g., mono-or polyfunctional vinylcyclopropanes or bicyclic cyclopropaneacrylatederivatives (cf. DE 196 16 183 C2 or EP 03 022 855) or cyclic allylsulphides (cf. U.S. Pat. No. 6,043,361 or U.S. Pat. No. 6,344,556),which, in addition, can also be used in combination with thedi(meth)acrylate crosslinking agents listed above. Preferred monomerswhich can polymerize by ring opening are such vinylcyclopropanes as1,1-di(ethoxycarbonyl)- or 1,1-di(methoxycarbonyl)-2-vinylcyclopropaneor the esters of 1-ethoxycarbonyl- or1-methoxycarbonyl-2-vinylcyclopropanecarboxylic acid with ethyleneglycol, 1,1,1-trimethylolpropane, 1,4-cyclohexanediol or resorcinol.Preferred bicyclic cyclopropane derivatives are2-(bicyclo[3.1.0]hex-1-yl)acrylic acid methyl or ethyl ester or thedisubstitution products in the 3 position thereof, such as(3,3-bis(ethoxycarbonyl)bicyclo[3.1.0]hex-1-yl)acrylic acid methyl orethyl ester. Preferred cyclic allyl sulphides are in particular theaddition products of 2-(hydroxymethyl)-6-methylene-1,4-dithiepane or7-hydroxy-3-methylene-1,5-dithiacyclooctane with2,2,4-trimethylhexamethylene 1,6-diisocyanate or the asymmetrichexamethylene diisocyanate trimer Desmodur® VP LS 2294 from Bayer AG.

Particularly suitable is the use of the calix[n]arenes corresponding tothe general formula (I) which can polymerize under cationic conditionsaccording to the invention in a mixture with known monomers which canpolymerize under cationic conditions by ring opening with low shrinkage,such as, e.g., glycidyl ethers or cycloaliphatic epoxides, cyclic keteneacetals, spiroorthocarbonates, oxetanes or bicyclic orthoesters.Examples are: 2-methylene-1,4,6-trioxaspiro[2.2]nonane,3,9-dimethylene-1,5,7,11-tetraoxaspiro[5.5]undecane,2-methylene-1,3-dioxepane, 2-phenyl-4-methylene-1,3-dioxolane, bisphenolA diglycidyl ether, 3,4-epoxycyclohexylmethyl3,4-epoxycyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl) adipate,vinylcyclohexane dioxide, 3-ethyl-3-(hydroxymethyl)oxetane,1,10-decanediylbis(oxymethylene)bis(3-ethyloxetane) or3,3-(4-xylylenedioxy)bis(methyl-3-ethyloxetane) or additional epoxidesmentioned in EP 0 879 257 B1. Silica polycondensates, which can beobtained, for example, by hydrolytic condensation of silanes carryinggroups which can polymerize under cationic conditions, preferably, e.g.,epoxide, oxetane or spiroorthoester groups, are also suitable as matrixsystems which can polymerize under cationic conditions. Such silicapolycondensates are described, for example, in DE 41 33 494 C2 or U.S.Pat. No. 6,096,903.

The dental materials according to the invention based on thecalix[n]arenes corresponding to the general formula (I) which canpolymerize under radical conditions can be polymerized using the knownradical initiators (cf. Encyclopaedia of Polymer Science andEngineering, Vol. 13, Wiley-Intersci. Pub., New York, etc., 1988,754ff.). Photoinitiators (cf. J. P. Fouassier and J. F. Rabek (Ed.),Radiation Curing in Polymer Science and Technology, Vol. II, ElsevierApplied Science, London and New York, 1993) for the UV or visibleregion, such as, e.g.: benzoin ethers, dialkyl benzil ketals,dialkoxyacetophenones, acyl- or bisacylphosphine oxides, or α-diketones,such as 9,10-phenanthrenequinone, diacetyl, furil, anisil,4,4′-dichlorobenzil and 4,4′-dialkoxybenzil and camphorquinone, areparticularly suitable.

Furthermore, azo compounds, such as 2,2′-azobis(iso-butyronitrile)(AIBN) or azobis(4-cyanovaleric acid), or peroxides, such as dibenzoylperoxide, dilauroyl peroxide, tert-butyl peroctoate, tert-butylperbenzoate or di(tert-butyl)peroxide, can also be used. Benzopinacoland 2,2′-dialkylbenzopinacols are suitable as initiators for heatcuring.

Combinations with aromatic amines are also frequently preferred in orderto accelerate the initiation using peroxides or α-diketones. Redoxsystems which have already proven to be worthwhile are: combinations ofbenzoyl peroxide or camphorquinone with amines, such asN,N-dimethyl-p-toluidene, N,N-di(hydroxyethyl-p-toluidene, ethylp-(dimethylamino)benzoate or structurally related systems. In addition,redox systems consisting of peroxides and such reducing agents as, e.g.,ascorbic acid, barbiturates or sulphinic acids are also suitable.

The dental materials according to the invention based on thecalix[n]arenes corresponding to the general formula (I) which canpolymerize under cationic conditions can be cured with the knowncationic photoinitiators, in particular with diaryliodonium ortriarylsulphonium salts, if appropriate in the presence of suitablesensitizers, such as, e.g., camphorquinone. Examples of suitablediaryliodonium salts which can be used in the visible region withcamphorquinone or thioxanthones as sensitizer are the commerciallyaccessible (4-octyloxyphenyl)phenyliodonium hexafluoroantimonate or(isopropylphenyl)(methylphenyl)iodoniumtetrakis(pentafluorophenyl)borate.

In addition, the dental materials according to the invention based onthe polymerizable calix[n]arenes can comprise one or more fillers,preferably organic or inorganic particulate fillers. Preferred inorganicparticulate fillers are amorphous spherical nanoparticulate fillersbased on oxides, such as pyrogenic silica or precipitated silica, ZrO₂and TiO₂ or mixed oxides of SiO₂, ZrO₂ and/or TiO₂ with a mean particlesize of 10 to 200 nm, minifillers, such as quartz, glass ceramic orglass powders with a mean particle size of 0.2 to 5 μm, and also fillerswhich are opaque to X-rays, such as ytterbium trifluoride ornanoparticulate tantalum(V) oxide or barium sulphate. In addition,fibrous fillers, such as glass fibres, polyamide fibres or carbonfibres, can also be used.

Finally, additional additives, such as, e.g., stabilizers, UV absorbers,dyes or pigments, and also solvents, such as, e.g., water, ethanol,acetone or ethyl acetate, or lubricants, can, if required, be added tothe dental materials according to the invention based on thepolymerizable calix[n]arenes.

In this connection, the dental materials according to the invention arecomposed, depending on the intended purpose, preferably of the followingcomponents:

Cements according to the invention preferably comprise:

-   -   (a) 0.5 to 30% by weight, particularly preferably 0.5 to 20% by        weight, of at least one polymerizable calix[n]arene according to        formula (I),    -   (b) 0.01 to 2% by weight, particularly preferably 0.01 to 1.5%        by weight, of initiator,    -   (c) 1 to 30% by weight, particularly preferably 5 to 20% by        weight, of at least one additional monomer which can polymerize        under cationic and/or radical conditions and/or one additional        monomer which can polymerize by ring opening, preferably a        polyfunctional (meth)acrylate,    -   (d) 5 to 70% by weight, particularly preferably 10 to 60% by        weight, of filler and    -   (e) 0.01 to 5% by weight, preferably 0.01 to 2% by weight,        particularly preferably 0.01 to 1% by weight, of additive,        the percentages each time adding up to 100%.

Filling composites according to the invention preferably comprise:

-   -   (a) 0.5 to 30% by weight, particularly preferably 0.5 to 20% by        weight, of at least one polymerizable calix[n]arene according to        formula (I),    -   (b) 0.01 to 5% by weight, preferably 0.01 to 2% by weight,        particularly preferably 0.01 to 1.5% by weight, of initiator,    -   (c) 1 to 30% by weight, preferably 5 to 20% by weight,        particularly preferably 5 to 15% by weight, of at least one        additional monomer which can polymerize under cationic and/or        radical conditions and/or at least one additional monomer which        can polymerize by ring opening, particularly preferably a        polyfunctional (meth)acrylate,    -   (d) 5 to 85% by weight, particularly preferably 10 to 80% by        weight, of filler and    -   (e) 0.01 to 5% by weight, preferably 0.01 to 3% by weight,        particularly preferably 0.01 to 2% by weight, of additive,        the percentages each time adding up to 100%.

Coating materials according to the invention preferably comprise:

-   -   (a) 1 to 70% by weight, particularly preferably 1 to 50% by        weight, of at least one polymerizable calix[n]arene according to        formula (I),    -   (b) 0.01 to 5% by weight, preferably 0.01 to 2% by weight,        particularly preferably 0.1 to 1.5% by weight, of initiator,    -   (c) 5 to 70% by weight, preferably 5 to 60% by weight,        particularly preferably 5 to 50% by weight, of at least one        additional monomer which can polymerize under cationic and/or        radical conditions and/or at least one additional monomer which        can polymerize by ring opening, particularly preferably at least        one polyfunctional (meth)acrylate,    -   (d) 1 to 30% by weight, preferably 3 to 20% by weight,        particularly preferably 3 to 15% by weight, of a filler,        preferably a nanoparticulate filler,    -   (e) 0.01 to 5% by weight, preferably 0.01 to 3% by weight,        particularly preferably 0.01 to 2% by weight, very particularly        preferably 0.01 to 1% by weight, of additive and    -   (f) 0 to 70% by weight, particularly preferably 0 to 30% by        weight, of solvent,        the percentages each time adding up to 100%.

Dental adhesives according to the invention preferably comprise:

-   -   (a) 0.5 to 50% by weight, particularly preferably 1.0 to 30% by        weight, of at least one polymerizable calix[n]arene according to        formula (I),    -   (b) 0.01 to 5% by weight, particularly preferably 0.01 to 2% by        weight, of at least one initiator,    -   (c) 5 to 70% by weight, particularly preferably 5 to 60% by        weight, of at least one additional monomer which can polymerize        under cationic and/or radical conditions and/or at least one        monomer which can polymerize by ring opening, particularly        preferably at least one polyfunctional (meth)acrylate,    -   (d) 0 to 30% by weight, particularly preferably 3 to 20% by        weight, of a filler,    -   (e) 0.01 to 5% by weight, particularly preferably 0.01 to 3% by        weight, of additives and    -   (f) 0 to 50% by weight, particularly preferably 0 to 20% by        weight, of solvent,        the percentages adding up to 100%.

The invention is more fully explained below with the help of examples.

EXAMPLE 1 Synthesis of a calix[6]arene tetramethacrylate V-9

R¹ to R⁶=random mixture of

9.6 g (15 mmol) of hexahydroxycalix[6]arene and 5.2 g (130 mmol) of 60%NaH in silicone oil are added to 80 ml of dry dimethylformamide in a 250ml flask with a nitrogen stopcock and stirred for 5 hours at AT.Subsequently, 5.2 ml (30 mmol) of octanoyl chloride are slowly added tothe suspension and stirred at AT for an additional 36 h. Subsequently,5.8 ml (60 mmol) of methacryloyl chloride are slowly added and stirredfor a further 72 h. The darkly coloured suspension is added to 600 ml ofwater, resulting in the precipitation of a white solid. This is filteredoff and copiously washed with water. The product is recrystallized fromtoluene and ethanol. The yield of product V-9 is 8.1 g. The MALDI-TOFanalysis of the product gave a substitution pattern of 2 octanoic acidgroups and 2-4 methacrylate groups.

EXAMPLE 2 Synthesis of a calix[6]arene dodecamethacrylate V-15

0.98 g of p-tert-butylcalix[6]arene (1 mmol), 0.16 g oftert-butylammonium bromide (TBAB) (1.8 mmol) and a spatula tip ofphenothiazine are mixed with 15 ml of N-methylpyrrolidone (NMP) andadded to a 50 ml round-bottomed flask. Subsequently, 4.3 g of glycidylmethacrylate (GMA) (30 mmol) are added to the solution. The charge isstirred at a temperature of 120° C. at a power of at most 100 watts for300 min in the microwave field. The clear brown solution obtained isprecipitated from 500 ml of water, filtration is carried out and finallydrying is carried out under high vacuum. The yield of product is 1.5 g.The MALDI-TOF analysis of the product gave a mixture of products of the1-6-fold reaction of p-tert-butylcalix[6]arene with GMA.

6 g of this calix[6]arene derivative are dissolved in 100 ml of CH₂Cl₂,mixed with 2.5 g of triethylamine (25 mmol) and stirred for 20 minutes.3.1 g of methacryloyl chloride (30 mmol), dissolved in 50 ml of CH₂Cl₂,are added dropwise to the solution in 2 hours at ambient temperatureunder nitrogen. Subsequently, the reaction mixture is stirred for afurther 4 days. The organic phase is then washed twice with each time150 ml of saturated NaHCO₃ solution and, finally, with 400 ml of H₂O.The organic phase is dried with Na₂SO₄ and the solvent is removed. Theyield of product V-15 is 8.5 g.

EXAMPLE 3 Synthesis of p-propyloxycalix[4]arenenitrone V-10

5,11,17,23-Tetraformyl-25,26,27,28-tetrapropoxycalix[4]arene (4.5 mmol)and N-methylhydroxylamine hydrochloride (27 mmol) are suspended in 60 mlof ethanolic NaOH (27 mmol) solution and stirred at ambient temperatureunder an N₂ atmosphere. After complete reaction has been achieved(FTIR), the reaction is brought to an end. Subsequently, the solvent isremoved on a rotary evaporator. The crude product is extracted byshaking with water/chloroform (each 100 ml). The cloudy organic phase isseparated and filtered and, subsequently, the solvent is removed on arotary evaporator. The product is dried under oil pump vacuum. Minimalamounts of impurity are separated by column chromatography withmethanol. The yield of product V-10 is approximately 100%.

EXAMPLE 4 Preparation of a Composite Cement Based on the polymerizablecalix[6]arene V-15 from Example 2

A composite fixing cement based on a methacrylate mixture (Material A,Comparison) and with incorporation of the calix[6]arene V-15 fromExample 2 (Material B) was prepared in accordance with the Table 1listed below using an “Exact” roller mill (Exakt Apparatebau,Norderstedt). Corresponding test specimens were prepared from thematerials, which were exposed to a dental light source (Spectramat®,Ivoclar Vivadent AG) for 2 times 3 minutes and accordingly cured. Theflexural strength and the flexural E-modulus were determined accordingto the ISO standard ISO-4049 (Dentistry—Polymer-based filling,restorative and luting materials). TABLE 1 Composite cement composition(figures in % by weight) Substances Material A Material B Triethyleneglycol dimethacrylate 39.6 31.8 Calix[6]arene V-15 from Example 2 — 7.8Aerosil OX-50 (Degussa) 41.3 41.3 Ytterbium trifluoride (Rhône- 18.718.7 Poulenc) Photoinitiator¹⁾  0.4 0.4¹⁾Mixture of camphorquinone (0.24% by weight) and ethylp-(N,N-dimethylamino)benzoate (0.26% by weight)

It is clear, from Table 2, that the material B, in comparison with thematerial A (based on a purely conventional methacrylate mixture), atleast results in comparable mechanical properties. TABLE 2 Cementproperties Material property Material A Material B Flexural strength(MPa) after 24 h 77 58 Flexural strength (MPa) after 24 h 71 62 SW¹⁾Flexural E-modulus (GPa) after 24 h 4.32 4.20 Flexural E-modulus (GPa)after 24 h 4.10 4.00 SW¹⁾SW = storage of the test specimens under water at 37° C.

EXAMPLE 5 Preparation of a Filling Composite Based on the polymerizablecalix[6]arene V-15 from Example 2

A filling composite based on a methacrylate mixture (Material C,Comparison) and with incorporation of the calix[6]arene V-15 fromExample 2 (Material D) was prepared in accordance with the Table 3listed below using an LPM 0.1 SP kneader (Linden, Marienheide). Testspecimens were prepared and cured from the materials analogously toExample 3. The flexural strength, the flexural E-modulus and thepolymerization shrinkage were determined according to the ISO standardISO-4049. TABLE 3 Filling composite composition (figures in % by weight)Substances Material C Material D Tetric monomer¹⁾ 18.1 16.3Calix[6]arene V-15 from Example 2 — 1.8 Glass filler GM27884 (Degussa)²⁾52.2 52.2 Sphärosil (Tokoyama Soda)³⁾ 14.5 14.5 Ytterbium trifluoride(Rhône- 15.0 15.0 Poulenc) Photoinitiator⁴⁾  0.2 0.2¹⁾Mixture of 42.4% by weight of Bis-GMA, 37.4% by weight of UDMA and20.2% by weight of triethylene glycol dimethacrylate,²⁾silanized Ba Al borosilicate glass filler with a mean particle size of1.5 μm,³⁾SiO₂/ZrO₂ mixed oxide (mean primary particle size: 250 nm),⁴⁾mixture of camphorquinone (0.24% by weight) and ethylp-(N,N-dimethylamino)benzoate (0.26% by weight)

TABLE 4 Filling composite properties Material property Material CMaterial D Flexural strength (MPa) after 24 h 140 121 Flexural strength(MPa) after 24 h 163 150 SW¹⁾ Flexural E-modulus (GPa) after 24 h 11.411.2 Flexural E-modulus (GPa) after 24 h 11.8 10.9 SW Polymerizationshrinkage (Vol %) −3.98 −3.22¹⁾SW = storage of the test specimens under water at 37° C.

It is clear, from Table 4, that the material D, in comparison with thematerial C (based on a purely conventional methacrylate mixture),results, with comparable mechanical properties, in a significantlyreduced polymerization shrinkage.

EXAMPLE 6 Preparation of a Filling Composite Based on the polymerizablecalix[6]arene V-9 from Example 1

A filling composite based on a methacrylate mixture (Material E,Comparison) and with incorporation of the calix[6]arene V-9 from Example1 (Material F) was prepared with the components in Table 5 using a VPL1.5 kneader (Grieser, Lampertheim). Test specimens conforming tostandard specifications were prepared and cured from the materials. Theflexural strength, the flexural E-modulus and the polymerizationshrinkage or the polymerization shrinking stress were determinedaccording to the ISO standard ISO-4049. TABLE 5 Filling compositecomposition (figures in % by weight) Substances Material E Material FTEGDMA¹⁾ 9.1 7.8 Bis-GMA 9.1 9.1 Calix[6]arene V-9 from Example 1 — 1.3Glass filler GM018-053 (Schott)²⁾ 76.0 76.0 Nano-SiO₂ ³⁾ 5.0 5.0Stabilizers 0.3 0.3 Photoinitiator⁴⁾ 0.5 0.5¹⁾Triethylene glycol dimethacrylate,²⁾silanized Ba Al borosilicate glass filler with a mean particle size of0.7 μm,³⁾SiO₂ dispersion (mean particle size: 20 nm),⁴⁾mixture of camphorquinone (0.36% by weight) and ethylhexylp-(N,N-dimethylamino)benzoate (0.14% by weight)

TABLE 6 Filling composite properties Material property Material EMaterial F Flexural strength (MPa) after 24 h 116 103 SW¹⁾ FlexuralE-modulus (GPa) after 24 h 7.8 7.9 SW Polymerization shrinkage (Vol %)−2.4 −1.8 Polymerization shrinking stress 5.9 5.4 (MPa) after 24 h SW¹⁾SW = storage of the test specimens under water at 37° C.It is clear, from Table 6, that the material F, in comparison with thematerial E (based on a purely conventional methacrylate mixture),results, with comparable mechanical properties, in a significantlyreduced polymerization shrinkage.

EXAMPLE 7 Preparation of a Filling Composite Based on the Crosslinkablecalix[6]arene V-10 from Example 3

A filling composite based on a methacrylate mixture (Material E,Comparison) and with incorporation of the calix[4]arene V-10 fromExample 3 (Material G) was prepared with the components in Table 6 usinga VPL 1.5 kneader (Grieser, Lampertheim). Test specimens conforming tostandard specifications were prepared and cured from the materials. Theflexural strength, the flexural E-modulus and the polymerizationshrinkage or the polymerization shrinking stress were determinedaccording to the ISO standard ISO-4049. TABLE 7 Filling compositecomposition (figures in % by weight) Substances Material E Material GTEGDMA¹⁾ 9.1 7.8 Bis-GMA 9.1 9.1 Calix[4]arene V-10 from Example 3 — 1.3Glass filler GM018-053 (Schott)²⁾ 76.0 76.0 Nano-SiO₂ ³⁾ 5.0 5.0Stabilizers 0.3 0.3 Photoinitiator⁴⁾ 0.5 0.5¹⁾Triethylene glycol dimethacrylate,²⁾silanized Ba Al borosilicate glass filler with a mean particle size of0.7 μm,³⁾SiO₂ dispersion (mean particle size: 20 nm),⁴⁾mixture of camphorquinone (0.36% by weight) and ethylhexylp-(N,N-dimethylamino)benzoate (0.14% by weight)

TABLE 8 Filling composite properties Material property Material EMaterial G Flexural strength (MPa) after 24 h 116 90 SW¹⁾ FlexuralE-modulus (GPa) after 24 h 7.8 6.5 SW Polymerization shrinkage (Vol %)−2.4 −1.7 Polymerization shrinking stress 5.9 4.6 (MPa) after 24 h SW¹⁾SW = storage of the test specimens under water at 37° C.

It is clear, from Table 8, that the material G, in comparison with thematerial E (based on a purely conventional methacrylate mixture),results, with slightly diminished mechanical properties, in asignificantly reduced polymerization shrinkage.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the inventive principles, it will beunderstood that the invention may be embodied otherwise withoutdeparting from such principles.

1. Dental materials comprising (a) 0.5 to 90% by weight of at least onepolymerizable calix[n]arene according to general formula (I),

(b) 0.01 to 5% by weight of initiator, (c) 0 to 90% by weight of atleast one additional monomer which can polymerize under cationic and/orradical conditions and/or which can polymerize by ring opening, (d) 0 to85% by weight of filler, (e) 0.01 to 5% by weight of additive and (f) 0to 70% by weight of solvent.
 2. Dental materials according to claim 1,comprising (a) 0.5 to 40% by weight of at least one calix[n]areneaccording to formula (I), (b) 0.01 to 2% by weight of initiator, (c) 1to 70% by weight of an additional monomer which can polymerize undercationic and/or radical conditions and/or which can polymerize by ringopening, (d) 3 to 80% by weight of filler and (e) 0.01 to 3% by weightof additive, the percentages each time adding up to 100%.
 3. Dentalmaterials according to claim 1, comprising calix[n]arenes of the generalformula (I):

in which n=1 to 5, R¹-R⁴=independently of one another, H, a C₁- toC₁₅-alkyl radical which can be interrupted by O, a phenyl radical or abenzyl radical, X¹ represents a group with the structure: Y¹—R_(a) ¹(Y_(a) ¹—R_(b) ¹—PG¹)_(m), in which Y¹=not present or O, ester, amide orurethane, R_(a) ¹=an m-valent organic radical which can comprise from 1to 30 carbon atoms and, if appropriate, also from 0 to 6 heteroatoms,such as O, S or N, m=1 to 3, Y_(a) ¹=not present or O, ester, amide orurethane, R_(b) ¹=not present or a C₁-C₁₆-alkylene radical which can beinterrupted by oxygen atoms, PG¹=a polymerizable group, e.g. a groupwhich can polymerize under radical conditions, such as (meth)acrylate,(meth)acrylamide, vinyl, allyl or styryl; a cyclic group which canpolymerize under radical conditions by ring opening, such as, e.g., thegroups

or a group which can polymerize under cationic conditions, such as,e.g., a vinyl ether or glycidyl group, a cycloaliphatic epoxide oroxetane group or a polymerizable nitrone group, with Y_(b) ¹=not presentor O, ester, amide or urethane, R_(c) ¹, R_(d) ¹=independently of oneanother, C₁- to C₁₅-alkyl radical which can be interrupted by O, aphenyl radical or a benzyl radical; and with furthermoreX²-X⁴=independently of one another, not present, OH or C₁- to C₁₀-alkylradical and which can have, independently of one another, the samemeaning of X¹ and, in addition, can represent a group with thestructure: (Y_(a) ²—R_(b) ²-AG)_(p), in which Y_(a) ²=not present or O,ester, amide or urethane, R_(b) ²=a p-valent organic radical which cancomprise from 1 to 20 carbon atoms and, if appropriate, also from 0 to 4heteroatoms, such as O or N, p=1 to 3 and AG=an anchoring group, such as—P═O(OH)₂, —O—P═O(OH)₂, —COOH or —O—SO₂OH.
 4. Dental materials accordingto claim 2, comprising calix[n]arenes of the formula (I):

in which n=1 to 3, R¹-R⁴=independently of one another, H, a C₁- toC₁₀-alkyl radical which can be interrupted by O, or a benzyl radical, X¹represents a group with the structure: Y¹—R_(a) ¹(Y_(a) ¹—R_(b)¹—PG¹)_(m), in which Y¹=not present or O or ester, R_(a) ¹=an m-valentorganic radical which can comprise from 1 to 15 carbon atoms and, ifappropriate, also from 0 to 3 oxygen atoms, m=1 to 2, Y_(a) ¹=notpresent or O or ester, R_(b) ¹=not present or a C₁-C₁₆-alkylene radicalwhich can be interrupted by oxygen atoms, PG¹=a polymerizable group, agroup, which can polymerize under radical conditions, such as(meth)acrylate or (meth)acrylamide, a cyclic group which can polymerizeunder radical conditions by ring opening, such as, e.g., the groups

or a group which can polymerize under cationic conditions, such as,e.g., a cycloaliphatic epoxide or oxetane group or a polyreactivenitrone group, with Y_(b) ¹=not present or O, ester or urethane, R_(c)¹, R_(d) ¹=independently of one another, C₁- to C₅-alkyl radical, aphenyl radical or a benzyl radical; and with furthermoreX²-X⁴=independently of one another, not present or C₁- to C₁₀-alkylradical and which can have, independently of one another, the samemeaning of X¹ and, in addition, can represent a group with thestructure: (Y_(a) ²—R_(b) ²-AG)_(p), in which Y_(a) ²=not present or Oor ester, R_(b) ²=a p-valent organic radical which can comprise from 1to 10 carbon atoms and, if appropriate, also from 0 to 2 oxygen atoms,p=1 to 2 and AG=an anchoring group, such as, e.g., —P═O(OH)₂,—O—P═O(OH)₂, —COOH or —O—SO₂OH.
 5. Dental materials according to claim1, comprising from 0.5 to 90% by weight of a calix[n]arene of theformula (I).
 6. Dental materials according to claim 1, additionallycomprising initiators, additional monomers which can polymerize undercationic conditions, monomers which can polymerize under radicalconditions, fillers and additives or one or more of these substances, 7.Dental materials according to claim 6, comprising, as monomers which canpolymerize under radical conditions, monomers which can polymerize byring opening, in particular mono- or polyfunctional vinylcyclopropanesor bicyclic cyclopropaneacrylates or cyclic allyl sulphides, andpolyfunctional (meth)acrylates or mixtures of these monomers.
 8. Dentalmaterials according to claim 1, the materials being cements comprising(a) 0.5 to 30% by weight of at least one calix[n]arene according toformula (I), (b) 0.01 to 2% by weight of initiator, (c) 1 to 30% byweight of at least one additional monomer which can polymerize undercationic and/or radical conditions and/or at least one additionalmonomer which can polymerize by ring opening, (d) 5 to 70% by weight offiller and (e) 0.01 to 5% by weight of additive, the percentages eachtime adding up to 100%.
 9. Dental materials according to claim 8,comprising (a) 0.5 to 20% by weight of at least one calix[n]areneaccording to formula (I), (b) 0.01 to 1.5% by weight of initiator, (c) 5to 20% by weight of at least one additional monomer which can polymerizeunder radical conditions and/or at least one additional monomer whichcan polymerize by ring opening, (d) 10 to 60% by weight of filler and(e) 0.01 to 3% by weight of additive, the percentages each time addingup to 100%.
 10. Dental materials according to claim 1, the materialsbeing filling composites comprising (a) 0.5 to 30% by weight of at leastone calix[n]arene according to formula (I), (b) 0.01 to 5% by weight ofinitiator, (c) 1 to 30% by weight of at least one additional monomerwhich can polymerize under ionic or radical conditions and/or at leastone additional monomer which can polymerize by ring opening, (d) 5 to85% by weight of filler and (e) 0.01 to 5% by weight of additive, thepercentages each time adding up to 100%.
 11. Dental materials accordingto claim 10, comprising (a) 0.5 to 20% by weight of at least onecalix[n]arene according to formula (I), (b) 0.01 to 2% by weight ofinitiator, (c) 5 to 20% by weight of at least one additional monomerwhich can polymerize under radical conditions and/or at least oneadditional monomer which can polymerize by ring opening, (d) 10 to 80%by weight of filler and (e) 0.01 to 3% by weight of additive, thepercentages each time adding up to 100%.
 12. Dental materials accordingto claim 1, the materials being coating materials comprising (a) 0.5 to70% by weight of at least one calix[n]arene according to formula (I),(b) 0.01 to 5% by weight of initiator, (c) 5 to 60% by weight of atleast one additional monomer which can polymerize under ionic or radicalconditions and/or at least one additional monomer which can polymerizeby ring opening, (d) 1 to 30% by weight of a filler, (e) 0.01 to 5% byweight of additive and (f) 0 to 70% by weight of solvent, thepercentages each time adding up to 100%.
 13. Dental materials accordingto claim 12, comprising (a) 1 to 50% by weight of at least onecalix[n]arene according to formula (I), (b) 0.01 to 1.5% by weight ofinitiator, (c) 5 to 60% by weight of at least one additional monomerwhich can polymerize under radical conditions and/or at least oneadditional monomer which can polymerize by ring opening, (d) 3 to 20% byweight of a filler, (e) 0.01 to 3% by weight of additive and (f) 0 to30% by weight of solvent, the percentages each time adding up to 100%.14. Dental materials according to claim 1, the materials being dentaladhesives comprising (a) 0.5 to 50% by weight of at least onecalix[n]arene according to formula (I), (b) 0.01 to 5% by weight of atleast one initiator, (c) 5 to 70% by weight of at least one additionalmonomer which can polymerize under radical conditions and/or at leastone additional monomer which can polymerize by ring opening, (d) 0 to30% by weight of filler, (e) 0.01 to 5% by weight of additives and (f) 0to 50% by weight of solvent, the percentages each time adding up to100%.
 15. Dental materials according to claim 14, comprising (a) 1 to30% by weight of a calix[n]arene according to formula (I), (b) 0.01 to2% by weight of at least one initiator, (c) 5 to 60% by weight of atleast one additional monomer which can polymerize under cationic and/orradical conditions and/or by ring opening, (d) 3 to 20% by weight offiller, (e) 0.01 to 3% by weight of additives and (f) 0 to 20% by weightof solvent, the percentages adding up to 100%.